openGauss每日一练第7天|《学习openGauss表空间》学习心得体会和课后练习

openGauss每日一练第7天|《学习openGauss表空间》学习心得体会和课后练习

学习目标

学习openGauss表空间

课程学习

表空间用于管理数据对象，与磁盘上的一个目录对应
课程学习

连接openGauss

#第一次进入等待15秒
#数据库启动中...
su - omm
gsql -r

1.创建表空间

–使用相对路径指定表空间的目录：数据库节点的数据目录/pg_location/相对路径

CREATE TABLESPACE ds_location1 RELATIVE LOCATION 'tablespace/tablespace_1';
omm=# CREATE TABLESPACE ds_location1 RELATIVE LOCATION 'tablespace/tablespace_1';
CREATE TABLESPACE
omm=# \db
              List of tablespaces
     Name     | Owner |        Location         
--------------+-------+-------------------------
 ds_location1 | omm   | tablespace/tablespace_1
 pg_default   | omm   | 
 pg_global    | omm   | 
(3 rows)

–指定owner

CREATE ROLE joe IDENTIFIED BY 'abce@123';
CREATE TABLESPACE ds_location2 OWNER joe RELATIVE LOCATION 'tablespace/tablespace_2';

–查看表空间信息

\db

omm=# \db
              List of tablespaces
     Name     | Owner |        Location         
--------------+-------+-------------------------
 ds_location1 | omm   | tablespace/tablespace_1
 ds_location2 | joe   | tablespace/tablespace_2
 pg_default   | omm   | 
 pg_global    | omm   | 
(4 rows)

2.修改表空间属性

–重命名表空间

ALTER TABLESPACE ds_location1 RENAME TO ds_location3;

–修改表空间owner

CREATE ROLE jay IDENTIFIED BY 'abcd@789';
ALTER TABLESPACE ds_location2 OWNER TO jay;

–查看表空间信息

\db

3.在表空间中建表

create table ds_t1(id int, name char(30)) tablespace ds_location2;

–通过视图查看表所在的表空间

select * from pg_tables where tablename = 'ds_t1';
omm=# \x
Expanded display is on.
omm=# select * from pg_tables where tablename = 'ds_t1';
-[ RECORD 1 ]-+-----------------------------
schemaname    | public
tablename     | ds_t1
tableowner    | omm
tablespace    | ds_location2
hasindexes    | f
hasrules      | f
hastriggers   | f
tablecreator  | omm
created       | 2021-12-07 11:28:46.31105+08
last_ddl_time | 2021-12-07 11:28:46.31105+08

4.删除表空间

–在删除一个表空间之前，表空间里面不能有任何数据库对象

drop table ds_t1;
DROP TABLESPACE IF EXISTS ds_location2;
DROP TABLESPACE IF EXISTS ds_location3;

课程作业

1.创建表空间，表空间tspc1使用相对路径指定所在目录，表空间tspc2指定owner为Lucy

create tablespace tspc1 RELATIVE LOCATION 'tablespace/tspc1';
CREATE ROLE lucy IDENTIFIED BY 'abce@123';
create tablespace tspc2 OWNER joe RELATIVE LOCATION 'tablespace/tspc2';

2.在表空间tspc1中建表，并使用视图pg_tables查看信息

create table test (id int) tablespace tspc1;
select * from pg_tables where tablename = 'test';
omm=# select * from pg_tables where tablename = 'test';
-[ RECORD 1 ]-+------------------------------
schemaname    | public
tablename     | test
tableowner    | omm
tablespace    | tspc1
hasindexes    | f
hasrules      | f
hastriggers   | f
tablecreator  | omm
created       | 2021-12-07 11:32:26.465598+08
last_ddl_time | 2021-12-07 11:32:26.465598+08

3.重命名tspc1，修改tspc2的用户为Lily，使用\db查看表空间信息

alter tablespace tspc1 rename to tspc3;
CREATE ROLE lily IDENTIFIED BY 'abce@123';
alter tablespace tspc2 owner to lily;
\db
omm=# CREATE ROLE lily IDENTIFIED BY 'abce@123';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# alter tablespace tspc2 owner to lily;
ALTER TABLESPACE
omm=# \db
List of tablespaces
-[ RECORD 1 ]--------------
Name     | pg_default
Owner    | omm
Location | 
-[ RECORD 2 ]--------------
Name     | pg_global
Owner    | omm
Location | 
-[ RECORD 3 ]--------------
Name     | tspc2
Owner    | lily
Location | tablespace/tspc2
-[ RECORD 4 ]--------------
Name     | tspc3
Owner    | omm
Location | tablespace/tspc1

4.删除表空间

drop table test;
DROP TABLESPACE IF EXISTS tspc1;
DROP TABLESPACE IF EXISTS tspc2;
DROP TABLESPACE IF EXISTS tspc3;
omm=# \db
List of tablespaces
-[ RECORD 1 ]--------
Name     | pg_default
Owner    | omm
Location | 
-[ RECORD 2 ]--------
Name     | pg_global
Owner    | omm
Location |